#define _GNU_SOURCE
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/stat.h>

char *mktemp(char *template)
{
    size_t l = strlen(template);
    int retries = 100;
    struct stat st;

    if (l < 6 || memcmp(template+l-6, "XXXXXX", 6)) {
        errno = EINVAL;
        *template = 0;
        return template;
    }

    do {
        __randname(template+l-6);
        if (stat(template, &st)) {
            if (errno != ENOENT) *template = 0;
            return template;
        }
    } while (--retries);

    *template = 0;
    errno = EEXIST;
    return template;
}
